AB is a current carrying conductor in the plane of the paper as shown in Figure 13.7. What are the directions of magnetic fields produced by it at points P and Q? Given r1 > r2, where will the strength of the magnetic field be larger?
According to Right Hand Thumb Rule, if all fingers of right hand we wrapped in a fist and thumb shows the direction of electric current, then direction of wrapped fingers shows the direction of magnetic field. In case of r1, the direction of magnetic field is towards the paper. In case of r2, the direction of magnetic field is out of the paper. Since r1 > r2, so strength of magnetic field at P is less than that at Q.
